Yes, the microwave oven is designed to be especially effective at one particular frequency. Look at the gasket on the inside surface of the door. Underneath is what is called a "quarter-wave choke". It looks like a short circuit at the surface of the door, but only at 2450 Mhz, the operating frequency of a microwave oven. You probably still got a lot of shielding, it just wasn't enough. Remember that modern communication receivers (even pocket pagers) are capable of working with incredibly small amounts of signal energy by human standards. And paging systems are designed to blanket their coverage areas with a *lot* of RF from multiple synchronized transmitters, each running several hundred watts. This seeming overkill is necessary to handle the very wide dynamic range in propagation losses that terrestrial communication links can encounter due to fading, multipath, terrain blockage, changing distances, etc. Even a properly operating microwave oven that is well within all radiation safety limits is *easily* detectable with a communications receiver or spectrum analyzer (the latter is preferable because the frequency is so unstable). I think I saw about -8dbm an inch from the door seal of the oven I had back in NJ when I checked it. As I said, this is well within biological safety limits but it is, by radio communication standards, an *extremely* strong signal. Amusing anecdote: recently I took one of our CDMA cellular phones into a supposedly NSA-certified RF screen room at work (though it's not used for government work). The cell antennas are on the roof of the same building. I closed the room door and latched it, and the phone still worked! I then put the phone into a conventional metal cabinet in the room and my call finally dropped. It's conceivable that the room still met specs (something like 100 dB), but that just wasn't enough until I added a few more dB with the metal cabinet. Like I said, mobile radio systems have to deal with some *very* wide dynamic ranges. Phil